Some distinct effects of tropical monsoon clouds as derived from atmospherics

Summary

The electrical effects due to monsoon clouds in conjunction with the VLF atmospherics data have been extensively analyzed. The cloud distribution and rainfall pattern during the SW monsoon period are examined. The diurnal curves of rainfall show that the maximum rain generally occurs in the afternoon hours between 13 to 18 IST. The coefficient of variation (CV) of monsoon rainfall plotted against rainfall amount reveals that CV decreases with increasing rainfall amounts upto about 40 inches. The differences in the mean dry bulb temperature as well as mean relative humidity values at the standard levels between strong and weak monsoon are studied. The monthly median of the hourly average together with the respective upper and lower decile values of atmospherics have been considered. Also, the frequency dependence of afternoon maximum (or late afternoon minimum) to morning minimum in the sferics level is taken into account to determine the seasonal variation. During monsoon months the sferics level with higher cloud amount (⩾4 okta) increases considerably but the width of the sferics is reduced. The results are interpreted by considering the activity of the sources involved at such times.